So this has been bugging me for awhile and I'm not entirely sure on this one. I've searched around the internet for some answers, but I still haven't really found a solid answer. My car will throw a P0306 code every once and awhile and from what I found, it's a 6th cylinder misfire? It will usually show up if I'm going a constant 50+mph for at least and hour or more. The code is not listed in my scanner's book nor my Haynes manual. I assume I have to change the spark plugs and wires (haven't done it yet because it's entirely too cold right now and I don't drive it enough currently, but I do have new plugs and wires ready to go). But is that all that could be causing the 'misfire'? Right before she throws the code, she idles rough and I start going through a lot of gas. It'll go off by itself though a few days later and I can always tell because she settles down and smooths out and I get my normal fuel efficiency/mileage. I'm just curious as to what this is, if there's more to it than just changing spark plugs and wires or if I should be looking for something else? I'm just wondering if anyone has any experience with this problem. BTW, she's a 98 3.8. v6 with 130K miles.

 

Start with the plugs and wires when weather permits. If they've never been changed, then it won't be a waste of time. Between the two, I would suspect a wire more. It also could be a bad #6 fuel injector, or a bad electrical signal to it. A bad coil is another possibility, but less likely since you're getting a single cylinder error, and one coil feeds two cylinders.

 

I assume the plugs/wires have probably never been changed since they're such a pita to do and expensive to have someone else do. Plus, the previous owner was not an intelligent person, so that's why I figured I'd start there. But thanks for the response, I'll keep an eye on the fuel injector if changing the plugs and wires don't seem to fix the problem. It's just something that has been bugging me because it comes and goes pretty randomly.